Currently, a terminal such as a smart phone, a Tablet PC and the like is generally equipped with a touch screen (or touch panel) with which users can use various functions of the terminal conveniently and efficiently, for example, chatting, dialing, working, taking pictures, playing games, shopping, watching videos and the like. Generally, the users conduct operations on the terminal by motions such as clicking or sliding on the touch screen of the terminal with fingers. However, when the touch screen of the terminal is in an unlocked state and if the fingers, arms or other parts of the users inadvertently touch or press the touch screen, the terminal will conduct actions triggered by touching or pressing, which may lead to misuse, such as dialing, deleting messages, opening a Web page, turning on the camera and the like, and this gives the users a lot of trouble. Therefore, how to provide a scheme that can effectively prevent the terminal from being operated accidentally has become an urgent problem to be solved.